分类： 心理学 >> 心理统计 提交时间： 2024-05-23
摘要： 成对研究以具有相互作用的两名个体为基本单元，广泛用于心理学领域涉及人际交互的研究中。它与密集追踪设计的结合有助于探究人际互动过程中个体行为与人际效应的动态变化，但目前尚缺乏能有效结合密集追踪数据特点以回答成对研究关心问题的统计方法。本研究拟通过模拟和实证研究，基于动态结构方程模型(Dynamic Structural Equation Modeling, DSEM)框架，探究三种人际互动模式(双人交互，一人与多人交互，多人两两交互)下密集追踪成对数据分析的统计模型的建构、拓展和应用，推动心理学研究更深入、科学地描述和解释人际交互情境中个体行为的动态发展过程及人际效应。
分类： 心理学 >> 心理学其他学科 提交时间： 2024-05-22
摘要： 基于I-PACE模型，通过2项实验考察了社交媒体相关信息对问题性社交媒体使用者的风险决策的影响。实验1使用财富之轮任务考察问题性社交媒体使用与风险决策之间的关系，结果发现问题组有更大的反应时和总注视时间、在高风险条件下更少地选择风险选项。实验2通过呈现社交媒体相关线索和中性线索测量社交媒体相关信息对问题性社交媒体使用者的风险决策的影响，结果显示，一致情况下增加了问题组的风险选项选择次数和首次到达时间。整个研究表明，问题性社交媒体使用会影响风险决策，社交媒体相关信息对问题组的影响更大，增加了其风险决策时的冒险倾向。未来可对问题性社交媒体使用者在风险决策过程中的大脑活动进行探究，以便深入了解问题性社交媒体使用与风险决策间的关系。
分类： 心理学 >> 心理学其他学科 提交时间： 2024-05-23
摘要： 网络适应作为当代青少年成长至关重要的环节，其复杂多维的内部属性仍未得到系统探讨。本研究首次采用网络分析方法探讨青少年网络适应的核心特征、动态演变以及外部联结。横断网络分析揭示了青少年的好奇心对网络适应的非线性影响，即过高或过低的好奇心均不利于网络适应的发展。交叉滞后网络分析表明，网络自我效能感在网络适应发展过程起“总舵手”作用，而网络信息搜索能力是青少年网络适应的重要“落脚点”。二元网络分析指出，网络信息保护能力对网络成瘾具有最显著的直接影响。本研究不仅为理解青少年在数字世界中的成功适应提供了全新视角，也为新时代的数字化教育实践提供了重要启示。
分类： 核科学技术 >> 核科学与技术 提交时间： 2024-05-21
摘要： 神经网络可以基于大量数据学习输入输出变量之间的关系，具有强大的拟合能力，在包括核工程计算领域常用作程序的代理模型。中子输运计算作为中子学模拟的核心环节之一，其耗时较长的问题可以通过利用神经网络模型来解决。然而，神经网络模型具有一系列超参数需要设置，而手动调节这些超参数工作量大，重复繁琐，只能依靠经验进行，而且求解不同问题时这些超参数不可复用。为了解决以上问题，本文提出了一种采用贝叶斯优化(Bayesian Optimization)算法来调节神经网络超参数，结合了学习率衰减、损失函数优化方法，它可以针对不同问题的数据集，自动搜索超参数的最佳组合，以获得最佳性能，具有很高的灵活性和效率，泛化性强。本文对 TAKEDA基准题得到的堆芯关键参数进行拟合，结果表明有效增殖因数keff的平均误差在150pcm以内，TAKEDA1数据集上区域积分通量Φ的平均误差率为1.72%，最大误差率为7.56%。该研究可为人工智能在堆芯物理计算理论的应用提供一定参考。
分类： 心理学 >> 管理心理学 提交时间： 2024-05-24
摘要： 本研究同时从死亡意识的消极层面和积极层面探讨和比较了不同死亡意识——死亡焦虑和死亡反省对亲社会行为的影响及其机制。研究一和研究二分别以亲社会倾向、公共物品博弈行为和真实的捐赠行为为指标，通过问卷调查和实验室实验考察了死亡焦虑和死亡反省对亲社会行为的影响，以及不同取向的价值观在其中的中介作用。结果表明：1)死亡焦虑负性预测或减少个体的亲社会行为倾向和行为；死亡反省正向预测或增加个体的亲社会倾向和行为。2)死亡反省和死亡焦虑对亲社会行为的影响是一个双路径中介机制。自我增强价值观在死亡焦虑对亲社会行为的影响中起中介作用；自我超越价值观在死亡反省对亲社会的影响中起中介作用。3)捐赠情境是死亡反省和死亡焦虑影响捐赠行为的调节变量。在公开捐赠情境下，死亡焦虑组被试的捐赠金额更高；在匿名捐赠情境下，死亡反省组被试的捐赠金额更高。捐赠情境分别正向和负向调节了死亡意识影响亲社会行为的两条中介路径。本研究揭示了死亡意识影响亲社会行为的积极效应机制和消极效应机制，为死亡意识的积极影响增加了进一步的证据支持。
分类： 天文学 >> 天文学 提交时间： 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： We present a study of star-forming galaxies (SFGs) with pseudobulges (bulges with Sérsic index n 2σ) mean of specific star formation rate (sSFR) enhancement (sSFRenh = 0.33 ± 0.07 versus sSFRenh = 0.12 ± 0.06) and broader scatter (by ∼1 dex). The eight SFGs that have the highest sSFRenh in the sample all have pseudobulges. A majority (69%) of paired SFGs with strong enhancement (having sSFR more than 5 times the median of the control galaxies) have pseudobulges. The Spitzer data show that the pseudobulges in these galaxies are tightly linked to nuclear/circum-nuclear starbursts. Pseudobulge SFGs in S+S and in S+E pairs have significantly (>3σ) different sSFR enhancement, with the means of sSFRenh = 0.45 ± 0.08 and −0.04 ± 0.11, respectively. We find a decrease in the sSFR enhancements with the density of the environment for SFGs with pseudobulges. Since a high fraction (5/11) of pseudobulge SFGs in S+E pairs are in rich groups/clusters (local density N1Mpc ≥ 7), the dense environment might be the cause for their low sSFRenh.
分类： 天文学 >> 天文学 提交时间： 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： Owing to the broad energy coverage of Insight-HXMT in the hard X-ray band, we detected the highest energy of pulsation exceeding 200 keV around the 2017–2018 outburst peak of the first Galactic pulsating ultraluminous X-ray source (PULX) Swift J0243.6+6124, which is the highest energy detected from PULXs to date. We also obtained the highest energy of pulsation of every exposure during the outburst in 2017–2018, and found the highest energy is roughly positively correlated with luminosity. Using our newly developed method, we identified the critical luminosity being 4 × 1038 erg s−1 when the main peaks of the low and high energy pulse profiles became aligned, which separates the fan-beam dominated and pencil-beam dominated accretion regimes. Above the critical luminosity, the phase of the main peak shifted gradually from 0.5 to 0.8 until the outburst peak in all energy bands is reached, which is in agreement with the phase shift found previously at low energies. Our result is consistent with what is derived from spectral analysis.
分类： 心理学 >> 应用心理学 分类： 心理学 >> 社会心理学 提交时间： 2024-05-26
摘要： 本研究探讨了产品属性和陈列秩序之间的匹配效应及其对消费者产品偏好的影响。基于联想学习理论，通过4个系列实验，发现产品属性和陈列秩序之间存在匹配关系，即产品的自然属性与无序陈列的关系更紧密，而产品的人工属性与有序陈列的关系更紧密，基于此提出了“自然-无序”与“人工-有序”的消费者朴素信念。这两种朴素信念进一步影响了消费者的产品偏好，当产品呈现自然属性(vs. 人工属性)时，消费者对无序陈列(vs. 有序陈列)下的产品产生更高的偏好，反之亦然，同时流畅性感知在其中起中介作用。进一步发现效价线索会在其中起到调节作用，效价线索的存在与否会改变消费者的产品偏好，即效价线索的出现显著提高了消费者对“自然-有序”和“人工-无序”的产品偏好及流畅性感知。这些结果说明了产品属性与陈列秩序之间存在密切联系，研究结论可为商家在商品陈列和广告营销的策略制定提供重要的实践启示。
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Correlated red noise recently reported from pulsar timing observations may be an indication of stochastic gravitational waves emitted by cosmic strings that formed during a primordial phase transition near the Grand Unification energy scale. Unfortunately, known probes of cosmic strings, namely the Cosmic Microwave Background anisotropies and string lensing of extragalactic galaxies, are not sensitive enough for low string tensions of $G\mu = 10^{-10}-10^{-7}$ that are needed to explain this putative signal. We show that strong gravitational lensing of Fast Radio Bursts (FRBs) by cosmic strings is a potentially unambiguous avenue to probe that range of string tension values. The image pair of string lensing are expected to have identical magnification factor and parity, and have a typical time delay of $\sim 10^2\,\,(G\,\mu/10^{-8})^2$ seconds. The unique spectral fingerprint of each FRB, as well as the possibility to detect correlations in the time series of the electric field of the radio waves, will enable verification of the string lensing interpretation. Very-Long-Baseline Interferometry (VLBI) observations can spatially resolve the image pair and provide a lower bound on the string tension based on the image separation. We calculate the FRB lensing rate as a function of FRB detection number for several different models of the FRB redshift distribution. We find that a survey detecting $\sim 10^5$ FRBs, in line with estimates for the detection rate of the forthcoming survey CHORD, can uncover a strong lensing event for a string tension of $G\mu \simeq 10^{-7}$. Larger FRB surveys, such as Phase 2 of the Square Kilometre Array (SKA), have the potential to significantly improve the sensitivity on the string tension to $G\mu \simeq 10^{-9}$.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： We measure for the first time the outermost edges of the Milky Way (MW) halo in terms of the depletion and turnaround radii. The inner depletion radius, $r_\mathrm{id}$, identified at the location of maximum infall velocity, separates a growing halo from the draining environment, while the turnaround radius, $r_\mathrm{ta}$, marks the outermost edge of infalling material towards the halo, both of which are located well outside the virial radius. Using the motions of nearby dwarf galaxies within $3\mathrm{Mpc}$, we obtain a marginal detection of the infall zone around the MW with a maximum velocity of $v_\mathrm{inf, max}=-46_{-39}^{+24}\mathrm{km s^{-1}}$. This enables us to measure $r_\mathrm{id}=559\pm 107 \mathrm{kpc}$ and $r_\mathrm{ta}=839\pm 121 \mathrm{kpc}$. The measured depletion radius is about 1.5 times the MW virial radius ($R_\mathrm{200m}$) measured from internal dynamics. Compared with halos in the cosmological simulation Illustris TNG100, the factor 1.5 is consistent with that of halos with similar masses and dynamical environments to the MW but slightly smaller than typical values of Local Group analogs, potentially indicating the unique evolution history of the MW. These measurements of halo edges directly quantify the ongoing evolution of the MW outer halo and provide constraints on the current dynamical state of the MW that are independent from internal dynamics.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The Solar System's orbital structure is thought to have been sculpted by an episode of dynamical instability among the giant planets. However, the instability trigger and timing have not been clearly established. Hydrodynamical modeling has shown that while the Sun's gaseous protoplanetary disk was present the giant planets migrated into a compact orbital configuration in a chain of resonances. Here we use dynamical simulations to show that the giant planets' instability was likely triggered by the dispersal of the gaseous disk. As the disk evaporated from the inside-out, its inner edge swept successively across and dynamically perturbed each planet's orbit in turn. The associated orbital shift caused a dynamical compression of the exterior part of the system, ultimately triggering instability. The final orbits of our simulated systems match those of the Solar System for a viable range of astrophysical parameters. The giant planet instability therefore took place as the gaseous disk dissipated, constrained by astronomical observations to be a few to ten million years after the birth of the Solar System. Terrestrial planet formation would not complete until after such an early giant planet instability; the growing terrestrial planets may even have been sculpted by its perturbations, explaining the small mass of Mars relative to Earth.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： A general covariant local field theory of the holographic dark energy model is presented. It turns out the low energy effective theory of the holographic dark energy is the massive gravity theory whose graviton has 3 polarisations, including one scalar mode and two tensor modes. The Compton wavelength is the size of the future event horizon of the universe. The UV-IR correspondence in the holographic dark energy model stems from the scalar graviton's strong coupling at the energy scale that marks the breaking down of the effective field theory.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Thermoelastic loss is one of the main energy dissipation mechanisms in resonant systems. A careful analysis of the thermoelastic loss is critical to design low-noise resonators for high-precision applications, such as gravitational-wave detectors. This paper presents an analytical solution to the thermoelastic loss in multimaterial coated finite substrates with realistic assumptions on the model structure and the elastic fields. The mechanism responsible for thermoelastic loss is taken as a function of material properties, operating temperature and frequency, and other design parameters. We calculate the thermoelastic loss for specific applications over a wide range of frequencies (1 Hz to 10 GHz) and temperatures (1 K to 300 K), and for a variety of substrate and coating materials. The result is relevant for gravitational-wave detectors and for experiments sensitive to mechanical dissipation.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Building accurate and predictive models of the underlying mechanisms of celestial motion has inspired fundamental developments in theoretical physics. Candidate theories seek to explain observations and predict future positions of planets, stars, and other astronomical bodies as faithfully as possible. We use a data-driven learning approach, extending that developed in Lu et al. ($2019$) and extended in Zhong et al. ($2020$), to a derive stable and accurate model for the motion of celestial bodies in our Solar System. Our model is based on a collective dynamics framework, and is learned from the NASA Jet Propulsion Lab's development ephemerides. By modeling the major astronomical bodies in the Solar System as pairwise interacting agents, our learned model generate extremely accurate dynamics that preserve not only intrinsic geometric properties of the orbits, but also highly sensitive features of the dynamics, such as perihelion precession rates. Our learned model can provide a unified explanation to the observation data, especially in terms of reproducing the perihelion precession of Mars, Mercury, and the Moon. Moreover, Our model outperforms Newton's Law of Universal Gravitation in all cases and performs similarly to, and exceeds on the Moon, the Einstein-Infeld-Hoffman equations derived from Einstein's theory of general relativity.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Presolar grains are microscopic dust grains that formed in the stellar winds or explosions of ancient stars that died before the formation of the solar system. The majority (~90% in number) of presolar silicon carbide (SiC) grains, including types mainstream (MS), Y, and Z, came from low-mass C-rich asymptotic giant branch (AGB) stars, which is supported by the ubiquitous presence of SiC dust observed in the circumstellar envelope of AGB stars and the signatures of slow neutron-capture process preserved in these grains. Here, we review the status of isotope studies of presolar AGB SiC grains with an emphasis on heavy-element isotopes and highlight the importance of presolar grain studies for nuclear astrophysics. We discuss the sensitives of different types of nuclei to varying AGB stellar parameters and how their abundances in presolar AGB SiC grains can be used to provide independent, detailed constraints on stellar parameters, including 13C formation, stellar temperature, and nuclear reaction rates.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Simple climate models have been around for more than a century but have recently come back into fashion: they are useful for explaining global warming and the habitability of extrasolar planets. The Climate App (https://www.climateapp.ca) is an interactive web-based application that describes the radiative transfer governing planetary climate. The App is currently available in French and English and is suitable for teaching high-school through college students, or public outreach. The beginner version can be used to explore the greenhouse effect and planetary albedo, sufficient for explaining anthropogenic climate change, the Faint Young Sun Paradox, the habitability of TRAPPIST planets and other simple scenarios. There is also an advanced option with more atmospheric layers and incorporating the absorption and scattering of shortwave radiation for students and educators wishing a deeper dive into atmospheric radiative transfer. A number of pedagogical activities are being beta tested and rolled out.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The Messenger Interface Monte-Carlo Mappings V (M^3) is a photoionization code adopting the fully self-consistent Monte-Carlo radiative transfer technique, which presents a major advance over previous photoionization models with simple geometries. M^3 is designed for modeling nebulae in arbitrary three-dimensional geometries. In this paper, we describe the Monte-Carlo radiative transfer technique and the microphysics implemented in M^3, including the photoionization, collisional ionization, the free-free and free-bound recombination, and two-photon radiation. We put M^3 through the Lexington/Meudon benchmarks to test the reliability of the new code. We apply M^3 to three HII region models with fiducial geometries, demonstrating that M^3 is capable of dealing with nebulae with complex geometries. M^3 is a promising tool for understanding emission-line behavior in the era of SDSS-V/LVM and JWST, which will provide high-quality data of spatially-resolved nearby HII regions and highly turbulent local and high-redshift HII regions.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The exchange of a pair of neutrinos between two objects, seperated by a distance $r$, leads to a long-range effective potential proportional to $1/r_{}^5$, assuming massless neutrinos and four-fermion contact interactions. In this paper, we investigate how this known form of neutrino-mediated potentials might be altered if the distance $r$ is sufficiently short, corresponding to a sufficiently large momentum transfer which could invalidate the contact interactions. We consider two possible scenarios to open up the contact interactions by introducing a $t$-channel or an $s$-channel mediator. We derive a general formula that is valid to describe the potential in all regimes as long as the external particles remain non-relativistic. In both scenarios, the potential decreases as $1/r_{}^5$ in the long-range limit as expected. In the short-range limit, the $t$-channel potential exhibits the Coulomb-like behavior (i.e. proportional to $1/r$), while the $s$-channel potential exhibits $1/r_{}^4$ and $1/r_{}^2$ behaviors.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： We show that the gravitational wave signals from primordial black hole (PBH) binaries at high redshift can be detected. The detectability of PBH binaries is enhanced by redshift bias and more PBH binaries at high redshift. The initial clustering of PBHs is also included and enhances the effectively detectable mass ranges of PBHs at high redshift. Future observations on the gravitational wave at high redshift by space-based detectors such as LISA and SKA can constrain the fraction of PBHs in dark matter and PBHs initial distribution.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Baiyang Bi
Miquel Barcelo
Christian Bauer
Faical Ait Benkhali
Jacqueline Catalano
Sebastian Diebold
Christian Föhr
Stefan Funk
Gianluca Giavitto
German Hermann
Jim Hinton
Ira Jung-Richardt
Oleg Kalekin
Ruben Kankanyan
Thomas Kihm
Fabian Leuschner
Marc Pfeifer
Gerd Pühlhofer
Olaf Reimer
Simon Sailer
摘要： In October 2019, the central 28 m telescope of the H.E.S.S. experiment has been upgraded with a new camera. The camera is based on the FlashCam design which has been developed in view of a possible future implementation in the Medium-Sized Telescopes of the Cherenkov Telescope Array (CTA), with emphasis on cost and performance optimization and on reliability. The fully digital design of the trigger and readout system makes it possible to operate the camera at high event rates and to precisely adjust and understand the trigger system. The novel design of the front-end electronics achieves a dynamic range of over 3,000 photoelectrons with only one electronics readout circuit per pixel. Here we report on the performance parameters of the camera obtained during the first year of operation in the field, including operational stability and optimization of calibration algorithms.
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